<!doctype html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>js</title>
</head>
<body>
	<p><img src="a.jpg" width="100px"></p>
	<p><img src="b.jpg" width="100px"></p>
	<p><img src="c.jpg" width="100px"></p>
</body>
<script>
	
	
	objs=document.images;
	
	for(i=0;i<objs.length;i++){
		
		objs[i].style.border='4px solid #000';
	}

</script>
</html>